1. Field of the Present Disclosure
The present disclosure relates to an image forming apparatus.
2. Description of the Related Art
An electrophotographic development system charges a surface of a photoconductor drum using a charging roller. Such process may apply to the charging roller (a) a charging voltage obtained by adding a direct current voltage and an alternating current to each other or (b) a direct current voltage as a charging voltage.
When charging a charging voltage obtained by adding a direct current voltage and an alternating current to each other to the charging roller, a surface potential of the photoconductor drum is set as a desired potential by detecting a current that flows into the charging roller and adjusting the detected current.
A characteristic of the photoconductor drum varies due to aging of the photoconductor drum, an environmental condition (machine outer temperature, machine outer humidity and/or the like), a usage situation (continuous usage time by now, the number of continuous printing paper sheets, and/or the like), and the like, and thereby the flowing current into the charging roller is changed to set the surface potential of the photo conductor drum as a desired potential, and consequently it is difficult to properly set the surface potential of the photoconductor drum on the basis of the flowing current and the like.
It should be noted that it is possible to properly set the surface potential of the photoconductor drum using a surface potential sensor, but such surface potential sensor is costly and therefore if such surface potential sensor is installed then the image forming apparatus is also costly.